<%@ page language="java" contentType="text/html; charset=UTF-8"
 pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>獲取圖片驗證碼</title>
<script type="text/javascript" src="${pageContext.request.contextPath }/static/js/jquery-1.10.2.min.js"></script>
</head>
<body>

 <form action="##" method='post'>
   <input type="hidden" id="userId" name="userId" value=""> 
    <div class="form-group">
     <div class="email controls">
      <input type="text" name='loginName' id="loginName" placeholder="用戶名" value="" class='form-control'/>
     </div>
    </div>
    <div class="form-group">
     <div class="pw controls">
      <input type="password" autocomplete="off" id="pwd" name="pwd" placeholder="密碼" class='form-control'/>
     </div>
    </div>

    <div class="form-group">
     <div class="email controls">
      <input id="validateCode" onblur="checkImg(this.value)" name="validateCode" type="text" class="form-control" placeholder="輸入驗證碼"/> 
     </div>
     <span class="y_yzimg"><img id="codeValidateImg" onClick="javascript:flushValidateCode();"/></span>
     <p class="y_change"><a href="javascript:flushValidateCode();" >換一張</a></p>
    </div>

    <div class="form-group">
     <span class="text-danger"></span>
    </div>

    <div class="submit">
     <div class="remember">

        <input type="checkbox" name="remember" value="1" class='icheck-me' data-skin="square" data-color="blue" id="remember">

      <label for="remember">記住我</label>
     </div>
     <input type="button" value="登錄" onclick="javascript:submitForm();" class='btn btn-primary'>
    </div>
   </form>

<script type="text/javascript">
$(document).ready(function() {
 flushValidateCode();//進(jìn)入頁面就刷新生成驗證碼
 });

/* 刷新生成驗證碼 */
function flushValidateCode(){
var validateImgObject = document.getElementById("codeValidateImg");
validateImgObject.src = "${pageContext.request.contextPath }/getSysManageLoginCode?time=" + new Date();
}
/*校驗驗證碼輸入是否正確*/
function checkImg(code){
 var url = "${pageContext.request.contextPath}/checkimagecode";
 $.get(url,{"validateCode":code},function(data){
 if(data=="ok"){
 alert("ok!")
 }else{
 alert("error!")
 flushValidateCode();
 }
 })
}

</script>

</body>
</html>

2、后臺代碼ImageGenController.java

package com.dufyun.springmvc.web.controller;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.stereotype.Controller;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import com.dufy.javaweb.test.RandomValidateCode;

@Controller
public class ImageGenController {


 @RequestMapping(value="/toImg")
 public String toImg(){

  return "image/image";
 }


 //登錄獲取驗證碼
 @RequestMapping("/getSysManageLoginCode")
 @ResponseBody
 public String getSysManageLoginCode(HttpServletResponse response,
   HttpServletRequest request) {
  response.setContentType("image/jpeg");// 設(shè)置相應(yīng)類型,告訴瀏覽器輸出的內(nèi)容為圖片
  response.setHeader("Pragma", "No-cache");// 設(shè)置響應(yīng)頭信息，告訴瀏覽器不要緩存此內(nèi)容
  response.setHeader("Cache-Control", "no-cache");
  response.setHeader("Set-Cookie", "name=value; HttpOnly");//設(shè)置HttpOnly屬性,防止Xss攻擊
  response.setDateHeader("Expire", 0);
  RandomValidateCode randomValidateCode = new RandomValidateCode();
  try {
   randomValidateCode.getRandcode(request, response,"imagecode");// 輸出圖片方法
  } catch (Exception e) {
   e.printStackTrace();
  }
  return "";
 }

 //驗證碼驗證
 @RequestMapping(value = "/checkimagecode")
 @ResponseBody
 public String checkTcode(HttpServletRequest request,HttpServletResponse response) {
  String validateCode = request.getParameter("validateCode");
  String code = null;
  //1:獲取cookie里面的驗證碼信息
  Cookie[] cookies = request.getCookies();
  for (Cookie cookie : cookies) {
   if ("imagecode".equals(cookie.getName())) {
    code = cookie.getValue();
    break;
   }
  }
  //1:獲取session驗證碼的信息
  //String code1 = (String) request.getSession().getAttribute("");
  //2:判斷驗證碼是否正確
  if(!StringUtils.isEmpty(validateCode) && validateCode.equals(code)){
   return "ok"; 

  }
  return "error";
  //這里我沒有進(jìn)行字母大小模糊的驗證處理，感興趣的你可以去試一下！
 }

}

3、生成驗證碼的工具類RandomValidateCode.java

package com.dufy.javaweb.test;


import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.util.Random;

import javax.imageio.ImageIO;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class RandomValidateCode {
 private Random random = new Random();
 private String randString = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";// 隨機(jī)產(chǎn)生的字符串

 private int width = 80;// 圖片寬
 private int height = 26;// 圖片高
 private int lineSize = 40;// 干擾線數(shù)量
 private int stringNum = 4;// 隨機(jī)產(chǎn)生字符數(shù)量

 /*
 * 獲得字體
 */
 private Font getFont() {
  return new Font("Fixedsys", Font.CENTER_BASELINE, 18);
 }

 /*
 * 獲得顏色
 */
 private Color getRandColor(int fc, int bc) {
  if (fc > 255)
   fc = 255;
  if (bc > 255)
   bc = 255;
  int r = fc + random.nextInt(bc - fc - 16);
  int g = fc + random.nextInt(bc - fc - 14);
  int b = fc + random.nextInt(bc - fc - 18);
  return new Color(r, g, b);
 }

 /*
 * 繪制字符串
 */
 private String drowString(Graphics g, String randomString, int i) {
  g.setFont(getFont());
  g.setColor(new Color(random.nextInt(101), random.nextInt(111), random
    .nextInt(121)));
  String rand = String.valueOf(getRandomString(random.nextInt(randString
    .length())));
  randomString += rand;
  g.translate(random.nextInt(3), random.nextInt(3));
  g.drawString(rand, 13 * i, 16);
  return randomString;
 }

 /*
 * 繪制干擾線
 */
 private void drowLine(Graphics g) {
  int x = random.nextInt(width);
  int y = random.nextInt(height);
  int xl = random.nextInt(13);
  int yl = random.nextInt(15);
  g.drawLine(x, y, x + xl, y + yl);
 }

 /*
 * 獲取隨機(jī)的字符
 */
 public String getRandomString(int num) {
  return String.valueOf(randString.charAt(num));
 }


 /**
 * 生成隨機(jī)圖片
 */
 public void getRandcode(HttpServletRequest request,HttpServletResponse response,String key) {

  // BufferedImage類是具有緩沖區(qū)的Image類,Image類是用于描述圖像信息的類
  BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_BGR);
  Graphics g = image.getGraphics();// 產(chǎn)生Image對象的Graphics對象,改對象可以在圖像上進(jìn)行各種繪制操作
  g.fillRect(0, 0, width, height);
  g.setFont(new Font("Times New Roman", Font.ROMAN_BASELINE, 18));
  g.setColor(getRandColor(110, 133));
  // 繪制干擾線
  for (int i = 0; i <= lineSize; i++) {
   drowLine(g);
  }
  // 繪制隨機(jī)字符
  String randomString = "";
  for (int i = 1; i <= stringNum; i++) {
   randomString = drowString(g, randomString, i);
  }
  //1：將隨機(jī)生成的驗證碼放入Cookie中
  Cookie cookie = new Cookie(key,randomString);
  response.addCookie(cookie);
  //2：將隨機(jī)生成的驗證碼放入session中
  String sessionid = request.getSession().getId();
  request.getSession().setAttribute(sessionid+key, randomString);
  System.out.println("*************" + randomString);

  //總結(jié)：這兩種方式都是很好，
  //（1）：使用cookie的方式，將驗證碼發(fā)送到前臺瀏覽器，不安全！不建議使用。
  //（2）：使用session的方式，雖然能解決驗證碼不發(fā)送到瀏覽器，安全性較高了，但是如果用戶量太大，這樣的存儲方式會對服務(wù)器造成壓力，影響服務(wù)器的性能。不建議使用。
  //這里暫時實現(xiàn)用這種方式，好的辦法是，在項目中使用的緩存，將生成的驗證碼存放到緩存中，設(shè)置失效時間，這樣既可以實現(xiàn)安全性也能減輕服務(wù)器的壓力。
  g.dispose();
  try {
   ByteArrayOutputStream tmp = new ByteArrayOutputStream();
   ImageIO.write(image, "png", tmp);
   tmp.close();
   Integer contentLength = tmp.size();
   response.setHeader("content-length", contentLength + "");
   response.getOutputStream().write(tmp.toByteArray());// 將內(nèi)存中的圖片通過流動形式輸出到客戶端
  } catch (Exception e) {
   e.printStackTrace();
  }finally{
   try {
    response.getOutputStream().flush();
    response.getOutputStream().close();
   } catch (Exception e2) {
    e2.printStackTrace();
   }
  }
 }

}

4、總結(jié)

本文的內(nèi)容到這就結(jié)束了，如果對里面的地方有不懂的地方，可以留言討論。希望本文的內(nèi)容對大家的學(xué)習(xí)工作能有所幫助。

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